Method of producing tubular ingots



June 6; 1933. a BROWNSTEIN 1,912,965

METHOD OF PRODUCING TUBULAR INGOTS Filed Oct. 21, 1930 3 Sheets-Sheet l June 6, 1933.

B. BROWNSTEIN METHOD OF PRODU GING TUBULAR INGOTS Filed Oct. 21, 1930 3 Sheets-Shet 2 'B, Bran/725702 June 6, 1933. B. BROWNSTEIN METHODOF PRODUCING TUBULAR INGO'IS Filed 001:. 21. 1930 3 Sheets-Sheet 3 gmwnio'a ,B. rwwmaiein Patented June 6, 1933 PATENT OFFICE BENJAMIN BROW'NBTEIN, OI REDWOOD CITY, PENNSYLVANIA METHOD PRODUCING TUBULAR IHGOTS Application fled October $1, 1880. Serial No. 490,229.

This invention relates to the art of making hollow ingots as a preparatory ste to makinlg seamless tubes, pipe and hollow siiafting. t was proposed a number of years ago to produce hollow ingots by casting the molten metal around a metallic core. This rocess is practically inoperative because of t e fact that molten metal while coolin and solidifying contracts, theforce pro uced by contraction increasing as solidification continues. Now when a core ofmetal is inserted in the mold and when molten metal is poured around it, the metal freezes around the core, while at the same time heating the core to a high temperature, which softens the core and causes it to become distorted in shape. This softening and distorted condition of the core, together with the contractive force of the metal cast around the core, makes it practically impossible to extract the core from the ingot, particularly so when the molten metal is in a large mass.

Another method proposed which is exemlified by the patent to James 442,895 of ecember 16, 1890, consists in piercing the ingot with a piercing bar while the metal is in a molten state. When piercing molten metal, the piercing bar must be kept in the molten metal long enough to allow the metal to set or solidify, and hence when that state arrives, the same conditions are present as previously referred to.

If the piercing bar is withdrawn too soon, the molten metal will 'flow out from the bottom and the result of this outflow can be readily conceived. In this patent the molten metal is pierced from the bottom and thus the mo ten metal is caused to leak out from the bottom, freezing around the piercing bar 40 and gripping it so that the piercing bar cannot be returned without sticking in the gland. This tends also to burn out the packing in the stufiing box when the gland gets excessively hot from the molten metal, but the process is particularly impractical in that difficulty in removing the core if made of .'.any kind of metal. Sand cores offer-the same 55 difficulties in removing them from the ingots. Hence the cost is very high, production a low and these two factors are enough to'prevent the process from being, adopted.

Hollow in ots roduced ,directly in the o0 ingot mold a ter t e molten metal 18 poured in the mold have never been made so far as I am aware, at least by any practical process.

It has also been proposed to make shells, 05 pipe and like articles by using a piercing press to roduce' the shell. but such articles are invariably made from short billets heated at a high temperature, pierced, drawn out in a hot draw bench and the crop ends cut ofi. The pipe resulting from this process are short in length and expensive.

If long lengths are required, they must be reheated and-rolled in a rollin mill and sized to the proper diameter. T ese operations add greatly to the production cost and hence are not used for regular pipe production.

In the last named process, the blanks, from which the shell or short section of pipe is to be made b a piercing bar are in the form of billets. billet is the result of many rolling passes after the ingot is cast in the mold, and hence in operating upon a billet, the operation is to be preceded by the followin operations, namely, (1) the ingot is cast; (2% stripped from the mold; (3) heated in a soaking pit; (4) rolled in a blooming mill into blooms; (5) cut into short lengths; (6) heated and rolled into billets and cut into,

short lengths for making pipef These operations, added to the operations for making pipe from the billet itself, make ten operations for making one to two lengths of pipe.

My improved method of making ingots is based upon the fact that when an ingot is cast, the metal cools from without, that is,

the exterior cools first and the interior cools last and by my process, broadly speaking, when the metal in the interior has cooled to a plastic condition, and is beyond, therefore, a molten condition, Ithen pierce the ingot, which at this time offers the least resistance to the piercing bar.

It is to be noted that in the above statement, I have referred to the metal of the ingot as being in a plastic condition. Plasticity, as defined in the Hand Book of the Bureau of Instruction, Carnegie Steel Company, page 5, is a physical property of matter which is opposite to elasticity. A plastic body once distorted will not regain its original shape. Steel though hard and in a cold state becomes plastic when heat is applied and when this eat is continued, it finally becomes liquid. Steel begins to become plastic or soft at about a temperature of 1,250 F. and continues to increase in plasticity until it reaches the melting point which is between 2,050" and 2,7 32 F. The variation in the melting point, of course, is due to the carbon content and to the constitution of different alloys. Steel while in a solid state is highly plastic due to the high heat which it contains and that is the condition of my ingot when I pierce it.

The steel in this condition has the greatest plasticity at the interior of the ingot and the least plasticity at the exterior or surface due to the lower temperature of the ingot mold and the natural heat radiation from the surface of the exposed metal. I pierce my ingot at from 50 to 100 below the temperature of complete solidification for at these tem eratures, the ingot possesses the greatest p asticity, hence offers the least re sistance to the piercing bar during the piercing operation.

It is, therefore, to be particularly understood that the ingot when it is pierced in accordance with my process is not in a weldable or pasty condition, the weldable point of low carbon steel. being-that condition in which the steel is in a pasty state close to the melting point, or, in other words, at the point where the scale begins to melt or the liquor begins to flow as stated on page 1055 of the Hand Book of the Carnegie Steel Company, Bureau of Instruction on the Making, Shaping and Treating of Steel.

Another reason and a particularly practical reason for piercingthe ingot when it is in its solidified or plastic condition is that steel in its liquid or pasty state cools very suddenly when brought in contact with a cooler body such, for instance, as the'pierc-- ing bar which is forced into the ingot, and while cooling shrinks considerably, grippin this cooler body with enormous force an holding it so that it cannot be extracted without either disrupting the press or the ingot mold. By piercing the ingot when it is in a plastic condition as opposed to a pasty condition, I eliminate this freezing of the metal on the piercing bar. If the metal of the ingot were at a welding heat, then the interior or core of the ingot would freeze on .the piercing bar and a cobble would result or else the frozen metal with the piercing bar would be ripped from the outer shell of the pierced ingot, leaving a badly ripped up and creviced interior from which a finished tube could not be made. When piercing a'steel ingot, however, that is completely .solidified but still in a plastic state, the fiow of metal as the piercing bar enters is laterally and upwardly and hence the metal does not grip the piercing bar with much force. This has been proven from actual practice by piercing billets with a piercing bar which is not tapered and it has been found that the stripping speed is not less than the piercing speed but that it takes less power to strip the piercing bar from the billet than it does to pierce it. Steel which is in a pasty or weldable state, however, does not flow away from the piercing bar but sticks to it with tenacious force, and cannot be extracted from it. Furthermore,'inasmuch as the metal is in a plastic condition, the piercing of the ingot causes all cracks and flaws to fill up under pressure and hence produces a sounder ingot. Now when a billet is heated .or an ingot is reheated, after it is cooled, even though it is still in a hot state but solldified, the exterior heats first and the interior heats last.

Hence to heat abillet so that the interior will be in the same plastic state as the ingot after it is cast, will cause the exterior to melt away as it is heated first. Therefore, piercing cannot be utilized as it can with the ingot. To pierce a short billet from which, for instance, a six inch shell is made takes 1,500,-

000 pounds of pressure whereas if the metal be in a plastic state, it would take one third or less of this pressure to pierce the billet, that is, a small billet from which'a three inch pipe is made. My invention contemplates casting the ingot in a mold, piercing the ingot in the mold while the metal is in a plastic state and offering the least resistance to the piercing bar, stripping the ingot from the mold with no crop end loss, or with a small crop end loss and cutting oil the crop end if a crop end ingot is' made.

Since ingots used in my process will weigh from 2,000 to 20,000 pounds, each, and the pipe lengths will weigh from 50 to 2,500 pounds each,'it will be seen that many pipes may be made from each ingot by my process as against one or two pipes made" by piercing a billet. Furthermore by my invention, less machinery and equipment is required,

thus meaning a cheaper production cost per panying drawings, wherein Figure 1 is a top plan view of an ingot mold, the stripper and piercing bar being shown in section; I v

Figure 2 is a Vertical sectional view through the ingot mold shown in Figurel;

Fi re 3 is a like view to Figure 2 but showing the piercing bar depressed through the stool to form a crop end on an ingot;

Figure 4 is an ingot formed with a protruding crop end;

Figure 5 is an ingot in which the piercing bar has not been moved through the end of the ingot;

Figured is a vertical sectional view of an ingot mold having'a modified form of stool and sliding means for holding a plug beneath the mold;

Figure 7 is a section on the line 77 of Fi re 6' Figure S is a like View to Figures but showing the plug supporting slides open and a ram supporting the center of the ingot while piercing is be ng accomplished;

Figure 9 is alike view to Figures 6 and 8 but showing the piercing bar as forcing the crop end of the ingot out;

Figure 10 is a like view to Figures 1 and 8. but showing a modification in the sliding means for supporting the ingot while being poured'and pressed;

Figure 11 is a fragmentary section as in Figure 10 showing the manner in which a punching bar is used to punch out the bottom of the ingot; I

Figure 12 is a like view to Figure 11, but showing a deeper slide and showing the operation of the punching bar to produce a cylindrical crop end;

Figure 13 is a .vertical sectional view'of an I ingot having a cylindrical crop end;

Figure 14 is a top plan view of an ingot showing the manner in which the sides will be curved to facilitate the later operations of rolling. a

Figure 15 is a longitudinal fragmentary sectional view through a modified form of in ct.

eferring to Figure 2, 10 designates an ingot mold such as isused for the production of the ingot A in'Figure 5. This ingot mold 10 is placed upon a stool 11, and clamped to the stool by clamps 12 engaging the mold or by any other suitable means. The stool I s annular in form to provide a central passage 13 and prior to the casting of the ingot a bottom plug 14 is dis osed in this opening and cemented in place y fire clay 15. The molten metal M is then poured into themold and allowed to cool until it is in a plastic state. The mold and the stool are then disposed in a press and a piercin bar 16 whose lower end is tapered to a rounded point to form a nose 17 is driven downward through the-top of the mold, that is, throu h the plastic metal within the ingot mold w ile the plu is supported by a ram 18 from below. e force holding the supporting ram is greater than .the force operating the piercing bar, hence allowing the piercing bar to pierce the ingot I press, clamps released, and the ingot mold removed from the stool. The ingot is then stri ped from the mold and the crop end a of t e ingot A or A is then cut off by a saw or torch, producing a complete hollow ingot from which any size pipe, tube .or hollow shaftin within the range of the ingot can be rolle The plug is removed from the supporting ram for use in the next mold.

In Figures 6 to 9, I have illustrated another ingotmold for producing 'such an ingot as that shown at A in Figure 4; The same reference numerals have been used for the stool, the ingot mold, the piercing bar and the stripper. In this case, however, the bottom plug 14 is supported by two supporting slides 20 located in slideways 20 formed in the stool. The top of the bottom plug is greased or oiled with heavy oil and fire clay 21 is applied to close the hole in the stool and cover the plug, the oil or grease acting to prevent the plug fromsticking to the clay when it is hardened.

The molten metal is then poured into the mold and when cooled to a plastic state, the supporting slides 20 are withdrawn by means of the slide operating levers 22 and 23 shown 23 at a point outward of its fulcrum pin so that the levers will operate in rections. a

that is, into a position to support the plu or shifted outward to releasethe plug. W en 1 the metal is cooled to a lastic state, the supporting slides are move by the handle 28 and the plug drops out from'the bottom of the stool. The ingot mold is then placed in a press having a piercing bar and a supporting ram, and is then operated on in the same manner as the ingot mold previously described. When the slides are closed and the plug is placedon the slides, a lock pin 29 is inserted through the stool and through an aperture formed in the lug 30 projecting through the lever 23 to thus lock the operating slide levers and prevent thev supporting slides from moving, thus keeping the plug in its pro r location in the stool.

In igures 10 to 11 I have shown an in ot mold for forming an ingot A. In these gures I have illustrated an ingot mold 10 which is formed of a steel casting and is provided with a cast iron inner mold shell 10. The stool 11 is formed with a slideway 31 in its base in which the slide designated generally 32 is movable. This slide may be shifted by' any suitable means. The slide is formed with an imperforate portion .33 designed to close. the bottom of the mold when the ingot is poured and while the piercing bar is operated and with a hole or aperture 34 extending entirely through the slide and which is designed to be brought beneath the center of the ingot,

- after the piercing bar has been withdrawn to permit a punch ar to be operated to punch out the bottom of the ingot. In using the construction shown in Figures 10 and 11 initially the slide 32 is so located that the bottom of the mold is closed.

The metal is then poured and when it is in a plastic state, the piercing. bar 16 is moved downward to a predetermined distance from the top of the slide. The movement of the piercing bar is then reversed and the piercing bar is withdrawn while the ingot is stripped fromthe piercing bar by the stripper 19. The ingot mold is then moved along the press base and brought in line with a punch bar 35 as shown in Figure 11 and then the slide 32 is shifted until the center line of the hole 34 is in alinement with the center line of the hole and the punch bar is then as is illustrated in Figures 10-to11 but-hav k ing a deeper section. The -slide32f in. this.

case has a hole 34.

1 offthis, a in barpismoved downward to a; redetersl mmed distance-from-jthe top of t eslide'e The-slideis then moved until the center line of the hole is in line with thecenter line of the mold andithen the piercing bar ismoved a further distance downward to a predetermined amount, producing the cylinder endof the ingot shown in Figure 4. The piercing bar is then withdrawn from the ingot, the stripper 19 preventing the ingot from being lifted from the, mold. The ingot mold is then moved along the press base and brought in line with the punchi bar which is moved down and the bottom of the cylinder end is punched out (see Figures 12 and 13), waste dro ping out through the hole in the bottom 0 the stool. The slide can be operated by any suitable means, as for instance, by hand or motor, through a rackand pinion and screw. This has not been shown inasmuch as many different means may be used for this purpose, all of which are obvious.

In Figures 10 to 12 I have illustrated the ingot mold as made in two parts that is, of an outer shell 10 and an inner she 10. This inner shell is made of cast iron and heated to a high temperature before itis placed in the mold, the outer shell being made of steel casting, which outer shell is thus cast around the cast iron core 10", with both at a high temperature. A good bond is formed when cooled and the inner shell willnot separate from the outer shell under heating and cooling. The inner shell df cast iron possesses high heating quality while the steel I casting outer shell possesses high tensile strength, thus making a strong and durable mold. The inner shell is made with a flange 10 at top and bottom overlapping the outer shell so as to form a positive connection between the shells and prevent the shells from being stripped apart when stripping the ingot from the mold. The stripper 19 which strips the ingot from' the plercin'g bar is attached to the press and operated by it. The ingot A shown in Figure 5 can be made in any one of the molds described. The ingot A shown in Figure 4 can be made in the Figures 3 and 9 by allowing the piercingbar to continue in its stroke until the cylinder end is ruptured, and opened to the full size of the piercing bar, making a hollow ingot with a hole from end to end. The ingots in Figures 4, 5 and 15 may all be cropped along the lines X-X indicated in the several figures. 1 The irregular metal at end of cylinder produced by rupture may be cropped after the ingot is stripped from the mold or '1 left until ingot is rolled into tubes or pipe 1. and: then cropped. l

The reason for producing a cylinderend "mold solidifies as it comes in contact w1th the ingot mold, hence it is far harder than the mass of metal in the center of the ingot after it has cooled to a plasticstate. Therefore, it cannot be pierced so easily as the inward and upward flow of the metal is very slow due to the hardness of the metal and also due to the great resistance of the large mass of'metal at the bottom of the ingot and more firmly held to the bottom and sides of the mold than the metal within the mass of the ingot. Second, in Fig. 5, a lar e part of the mgotis left as a crop end whic is expensive waste. Third, it is far. easier to draw out the bottom of the pierced ingot into asmall cylinder than to cause the metal to flow inward and upward in a confined space as the case happens to be in the bottom of the ingot mold. Fourth, the crop end produced by the cylinder end shown in Figures 13, 15

I and 4 is the least expensive crop end waste.

It is to be understoodthat in Figure5 an ingot is shown in which the piercing bar is stopped in its movement before reaching the extremity of the ingot and that under these circumstances, the ingot will be cutoff on the line XX, 'or the crop end punched out by punch bar as shown in Figure 11, the crop end a being thrown away or remelted. In Figure 4, the ingot is shown as having its crop end formed by forcing the piercing bar entlrely through the ingot mold, the crop end being cut off on the line X-X. The ingot shown in Figure 13 is made by forcin the piercing bar through the ingot mold, orming the ingot shown in Figure 4 and then. followed by f )rcin the punching bar 35 into the ingot and punc ing the bottom out fi'om the cylinder. The ingot shown in Figure 15 is made b forcing the piercing bar through the closed cylindrical portion and the crop end XX is cut oil. 7 In all forms of my apparatus and in all the steps of the processes described by me, an in ot is formed which after its end is cropped 1s tubular and which may be thereafter rolled to form tubes, pipes,

hollow shafts or other like tubular objects.

It is to be understood that the ingot and the corresponding mold may have any desired cross section, that is, approximately round, elliptical, triangular or rectangular. In Figure 14, the sides of the ingot are shown as curved instead of straight. This is because curved sides are less apt to sag or collapse. Hence the' mandrel barwith the plug will enter the hole of the ingot more easily and there will be less trouble from that source during the rolling in the first pass. Of

entirely upon the she. e of the mold and the and cut into proper length blooms.

4. Theblooms are examined for surface cracks or seams and the cracks or seams are chipped out, sand blasted or the surfaces are machined by a special planer. The reason for this operation is due to spiral or angular twisting of the material by the piercin rolls during piercing and defects in the sur ace of the billet are opened up by the angular twisting which results in defective tubes or pipe.

5. The blooms are heated in a continuous or other type of furnace.

6. The blooms are rolled in a billet or bar mill and cut into pro er length billets.

7. The billets are reheated in a continuous furnace.

8. The reheated billets are pierced in a disc or roll piercing mill thus producing outer rough walled tubes. When two piercing mills are used, the second piercing mill is used for expanding the pierced tube to larger diameter.

9. The pierced tubes are rolled in a rolling mill equipped with stripper rolls for returning the tube after each rolling.

" 10. The rolled tubes are reeled in a reeling machine which smooths out the wrinkles which the rolling mill failed to smooth out. These wrinkles or rough spirals are produced by the piercing mill during piercing whether disc or roll piercing mill is used.

11. The reeled tubes are sized in a sizing machine and is the last milloperation, bringing the tube or pipe to proper diameter, producinga finished hot tube or pipe. They are then cooled. V i

12. The hot finished tubes are cut to proper len th, straightened,-'inspected, tested and oiled or shipping or stocked. Pipe are cut to random lengths, straightened, threaded, inspected, tested and oiled. In some mill layouts the straightening is done right after the pipe leave the cooling table after which follow the cutting off and threading o erations, each billet producing but one tu e or pipci.

y direct process for making seamless tubes or pipe is as follows 1. The ingots are poured and partly cooled.

2. The partly cooled ingots are pierced and stripped.

,3. The crop ends are cut off from the pierced ingots.

4. The pierced ingots are reheated in a soaking pit furnace.

5. The reheated ingots are rolled in a continuous rolling mill and sized in the last passes to the proper diameter;

6. The long length of tube or pipe after leaving the rolli mill is cut into many standard or other ength tubes or pipe and ent indirect process. Hence it is, therefore,

cheaper in cost of Ian machine and o erating costs per tu e or pipe. pro uced. y direct process any size of tu e, pipe or hollow shaft in any length can be produced.

I claim 1. A' method of making hollow ingots which consists in filling an ingot mold'with molten metal, allowing the metal to 0001 until it is completely solidified but yet in a plastic condition and then while'the metal is in the plastic state, forcing a piercing bar longitudinaly into the center of the ingot and withdrawing the piercing bar.

2. A method ofmaking tubular ingots which consists. in filling an ingot mold with molten metal, allowing the metal to cool to such a degree that the metal is entirely solidified but still in a plastic state, forcing a piercing bar longitudinally into the center of the ingot while the metal isstill in a plastic state, withdrawin the piercing bar and cropping off the, close end of the ingot.

3. A method of making tubular ingots which consists in filling an ingot mold with molten metal, allowing the metal to cool to a degree where the metal is entirely solidified but yet plastic with the central portion of the ingot in a more plastic state than the outer portion of the ingot, and then while the in terior of the metal is still plastic, forcing a piercing bar longitudinally into the center of the mgot. q

4. A method of making tubular ingots which consists in filling an ingot mold with molten metal, allowin the metal to cool until the metal is solidifiediut plastic and forcing a piercing bar longitudinally through the center of the ingot and while the interior of the ingot is still in a plastic state, withdraw-' ing the piercing bar and cropping off that portion of the metal which has been forced out beyond the ingot by the piercing bar 5. A method 0 ma ing tubular ingots which consists in filling an ingot mold with molten metal, allowing the metal to cool until the metal of the ingot is entirely solidified but yet in a plastic state, supporting the ingot at the central portion at one end, forcing a piercing bar longitudinally into the center of the in t, and within a predetermined distance rom the supporting means, removing the central supporting means, and

forcing the piercing bar through the ingot to close said central opening, filling the mold with molten metal, allowing the molten metal to cool until the metal has solidified but is in a plastic condition, forcing a piercing bar into the center of the in ot, and toward the closed end of the mol removing the central supporting member and forcing the piercing bar through the end of the ingot to thus form a closed projecting crop end, removin the piercing bar, strip ing the ingot from t e mold, and cutting o the cropend.

7. A method of making tubular ingots which consists in usin a mold open at both ends, mounting the mold upon a stool having a central opening, disposing a supporting member to temporarily close the central 0 ening, filling the mold with molten metal, a lowing the metal to cool until the ingot is completely solidified but is in a plastic state, forcing a piercing bar through the central portion of the ingot toward the supported end thereof while the metal is still plastic, withdrawing the piercing bar, withdrawing the supporting element from the central part of the stool forcing a-punch bar through theinterior of the now hollow ingot and punching out the end thereof through the opening in the stool.

8. A method of making tubular ingots which consists in filling an ingot mold with molten metal, allowin the metal to cool until it is completely soli ified but in a plastic condition, forcmg a piercing bar longitudinally through and beyond the end of the ingot while the interior of the ingot is still in a lastic state, forcing a punch bar throng the interior of the now hollow ingot and punching out the end of the ingot by I the punch bar and cro ping off a portion of the metal which exten 5 beyond the body of I the in 0t.

9. method of making tubular in ots which consists in usin a mold open at 0th ends, mounting the mo dupon a stool having a central opening, disposin a supporting member in said central opening to close the opening, filling the mold with molten metal, allowing the metal to cool until the metal is completely solidified but is in a plastic state, forcing a piercin bar longitudinally through the center .0 the ingot for a predetermined distance from the supporting member while the metal is in a plastic state, withdrawing the supporting member and allowing I the piercing bar to continue in its downward movement to another predetermined distance beyond the body 0 the ingot, forming a projected cylinder, withdrawing the piercing bar from the ingot and moving a punch bar into the now hollow ingot and punching out the end of the projected cylinder of the ingot, waste dropping out through the hole in the bottom of the stool.

In testimony whereof I hereunto afiix my signature.

BENJAMIN BROWNSTEIN. 

